Use Your Head! (to control your Mac, that is…) — Apple World Today

Once the two boxes are checked , moving your head up and down and side to side moves the mouse pointer around on the screen. While this is a fascinating trick, it doesn’t let you do much, so these controls allow you to emulate all of the usual mouse/trackpad actions with facial gestures.

3 – Click the Options… button next to Enable alternative pointer actions. Here you can assign facial expressions — Smile, Stick Out Tongue, Open Mouth, and Raise Eyebrows — to various pointer actions. In the screenshot below, I’ve assigned Smile to double-click, Open Mouth to left click, Stick Out Tongue to Drag and Drop, and Raise Eyebrows to do a right click.